R3765/67G Series Network Analyzer Operation Manual
7.7 Time Domain Function(OPT 70)
7-85
When the distance display mode is set, the horizontal axis is transformed from time to dis-
tance using the following formula.
L = c
×
V
f
×
T
Where,
L := Distance(m)
c := Velocity of light
≅
3
×
10
8
V
f
:= Velocity factor (Note)
T := Time(s)
When the reflection from the cable is measured, the actual physical distance is half of the
measured distance because the measured distance is equivalent to a round-trip path
where the signal goes and returns. For this reason, values of time and distance are cut in
half and displayed as the {REFLECTION TIME} and {REFLECTION DISTANCE}
measurements.
Note:
Set the velocity factor using {VELOCITY FACTOR}.
The velocity factor of Teflon and polyethylene dielectric is approximately 0.07
and 0.66, respectively.
(3)
Magnification of the time axis domain
The time span Tspan in the time axis domain is determined by the frequency span Fspan
and the number of measurement points N.
The waveform in the time domain can be magnified by changing the time range settings
([START], [STOP], and [SPAN]). [START] and [STOP] can freely be set within the range of
-Tspan to Tspan. (Note)
The magnification rate z automatically changes starting from the set time range. The time
span T’span that is actually displayed is represented by the following expression.
Note: If the time span exceeds Tspan, the displayed data includes redundant
information.
T
span
=
N-1
F
span
T’
span
=
N-1
F
span
×
Z
